The present invention is related to articles of composite construction including reinforced synthetic resins, and in particular relates to such articles finished to resemble the appearance of real wood.
Real wood, finished by staining and provision of a protective coating such as natural or synthetic lacquer, varnish, or resin finishes, has a pleasing appearance and a substantial and solid feel. Many species of wood having a desirable appearance, however, such as most hardwoods, are expensive and require considerable amounts of skilled labor and time for production of finished articles. The appearance of wood with a bright finish, that is, a finish exposing the color and texture of the wood grain, is particularly desirable for exterior doors and entryway structures, although they may be quite expensive to construct of real wood.
While the appearance of wood is very pleasing for entryways and other exterior features of building, wood is susceptible to damage caused by weather and insect pests, which can destroy the wood or damage its finish. Frequent and often costly maintenance is thus required to prevent rapid deterioration of the appearance of real wood with a bright finish exposed to the weather.
As a more economical substitute, then, entryway doors and numerous other products for which the appearance of wood is desirable have recently been made of composite construction including outer layers of fiber-reinforced synthetic resins prepared to resemble wood. The appearance of such previously available imitation wood products, however, has at best failed to match the attractiveness of well-made structures of actual wood with a bright finish.
While some products of plastics and composite construction have been molded to include surface texture resembling the grain of wood, the appearance of depth that is so attractive in real wood has previously not been possible to reproduce in the finish of such articles. For example, Mrozinski U.S. Pat. No. 5,399,373 discloses production of imitations of natural wood by molding a resin-based gel coat to include a surface shape closely copying the surface grain texture of real wood. For this layer Mrozinski teaches the use of a pigmented gel coat material whose color is related to the color of the wood being imitated. Mrozinski""s process also requires the use of artists"" oil colors or similar pigments to fill the surface texture to imitate the appearance of real wood. The use of such artists"" oils, however, requires considerable skill and time, and still results in an appearance somewhat lacking in realism.
Doors and other entryway components frequently include panels surrounded and supported by moldings attached to larger frame members. Such panels, particularly glass panels of doors and entryway sidelights, have to be supported securely with respect to the surrounding frames. The weight of large multi-layered glass panels, particularly when they include decorative panes assembled in metal caming, can be significant. Moldings used to attach such glass panels to frame structures must therefore be held securely in the required locations on a door or other frame structures.
While adhesives are the primary mechanism for interconnecting the parts of synthetic resin composite structures, fasteners extending through the moldings have also been required in previously known doors and other structures of composite construction in order to ensure that heavy glass panels are held securely enough. The holes through the moldings where such fasteners have been installed have then had to be plugged and finished to match the surrounding surfaces of the moldings, requiring significant time and skill.
What is desired, then, is an improved composite construction including synthetic resin surface portions that can be finished to provide an attractive pleasing appearance closely resembling finished natural wood, while avoiding the disadvantages of natural wood. It is also desired to be able to secure moldings to the skins or other components of a door or other structure of composite construction without having to use fasteners that extend through the moldings to their exterior surfaces.
The present invention provides an answer to the above-stated need for a product of composite construction having an appearance closely imitating real wood, by providing a structure for the exterior skin of a product of composite materials incorporating synthetic plastics that when finished has the appearance of real wood, and by providing a method for making such products.
As first aspect of the invention, an article manufactured of composite materials and having an appearance closely resembling real wood includes an outer layer of a transparent resin-based gel coat material whose outer surface is molded to incorporate in detail the grain shape of the surface of bare real wood. A subsurface layer adjacent to the surface layer of transparent gel coat material is of pigmented resin-based gel coat material of a color related to or resembling the color of unfinished wood of the type whose surface shape is represented. Beneath the subsurface layer is a structural supporting layer which may be of a suitable synthetic resin, reinforced as by glass or other fibers.
When an appropriate finish, such as a wood stain and a protective coating such as laquer, varnish, urethane, or another suitable synthetic resin, is applied to the outer surface of the outer layer of clear gel coat material, the resulting appearance of such a structure according to the invention has a remarkable resemblance to real wood with a similar stain and protective finish. An article constructed according to the invention and provided with such a finish presents an appearance of depth closely resembling the appearance of real wood with a similar type of finish.
In one preferred embodiment of this aspect of the invention the outer layer of transparent gel coat is substantially completely clear and colorless.
In one preferred embodiment of this aspect of the invention the outer layer of transparent gel coat has an average thickness in the range of about 0.012 to 0.020 inch, while the subsurface layer of pigmented gel resin has an average thickness in the range of about 0.003-0.010 inch.
A second major aspect of the present invention is the method of manufacturing an article of composite structure by providing a first skin sheet including an outer layer of transparent gel resin molded to incorporate a surface shape imitating the grain of real wood; providing a second skin sheet, fastening the skin sheets to opposite faces of a frame structure; filling the cavity defined between the skin sheets and within the frame structure with a structural synthetic resin foam adhering to the frame structure and the skin sheets; curing the resin foam and thereby forming a substantially rigid core structure interconnecting the skin sheets and frame; and applying a protective finish coating to the outer surface of the outer layer of at least the first skin sheet.
A third aspect of the present invention is the provision of an article of composite construction resembling an article of real wood and including fasteners fixedly mounted in moldings and used to locate the moldings precisely with respect to an article of composite construction without the use of fasteners extending entirely through such moldings so that unsightly plugs and difficult finish work are not needed.
The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.